Cleaning method
AssigneeFSI International, Inc.
InventorsJeffery W. Butterbaugh, David C. Gray
Life of this patent
Estimating the term…
Abstract
A method for removing native oxides and other contaminants from a wafer surface while minimizing the loss of a desired film on the wafer surface. The method is carried out in a hermetically sealed reactor. A fluorine-containing gas or gas mixture is passed over the wafer during simultaneous exposure to ultraviolet radiation in the absence of added water, hydrogen, hydrogen fluoride or hydrogen containing organics, thereby avoiding the production of water as a reaction product. The addition of ultraviolet radiation and the elimination of water, hydrogen, hydrogen fluoride and hydrogen containing organics provides for the nearly equivalent (non-selective) removal of various forms of oxide and also provides for improved process control.
Claims38
A method for cleaning a surface of a substrate, the substrate being formed of a silicon, silicon dioxide or gallium arsenide material and the substrate surface having thereon an undesired material to be removed from the surface of the substrate, the undesired material comprising a first silicon oxide material, the substrate surface also having thereon a second silicon oxide material which is different from the first silicon oxide material and which is desired to be retained on said substrate after performance of said method, the second silicon oxide material being selected from the group consisting of doped silicon oxide, deposited silicon oxide, and thermally grown silicon oxide, the method comprising the steps of:
- placing the substrate in a gaseous environment comprising at least one fluorine containing gas selected from the group consisting of fluorine and fluorine containing gases, other than F.sub.2 O, which are free of hydrogen and which can be photodissociated with light of a wavelength in the range of 180-600 nm, the gaseous environment being substantially free of plasma products, water, hydrogen, hydrogen fluoride and hydrogen containing organic compounds, and
- exposing the substrate to UV irradiation in the presence of the gaseous environment until the first silicon oxide material has been removed.
A method for cleaning a surface of a substrate, the substrate being formed of a silicon, silicon dioxide or gallium arsenide material and the substrate surface having thereon an undesired material to be removed from the surface of the substrate, the undesired material comprising a first silicon oxide material, the first silicon oxide material formed as a result of ambient exposure of the wafer surfaces or formed as an incidental result of wet or gaseous chemical processing steps, the substrate surface also having thereon a second silicon oxide material which is different from the first silicon oxide material and which is desired to be retained on said substrate after performance of said method, the second silicon oxide material being a doped silicon oxide, the method comprising the steps of:
- (a) evacuating a hermetically-sealed processing chamber to a low base pressure,
- (b) introducing a silicon wafer substrate into the processing chamber,
- (c) introducing into said chamber and exposing the silicon wafer in said chamber to a gaseous environment comprising at least one fluorine containing gas selected from the group consisting of fluorine and fluorine containing gases, other than F.sub.2 O, which are free of hydrogen and which can be photodissociated, the gaseous environment being substantially free of plasma products, water, hydrogen, hydrogen fluoride and hydrogen containing organic compounds,
- (d) exposing the gaseous environment and substrate in said chamber to ultraviolet light,
- (e) evacuating the processing chamber, and
- (f) removing the substrate from the processing chamber.
A method of removing an undesired material comprising a first silicon oxide material from a surface of a silicon, silicon oxide or gallium arsenide substrate, the substrate comprising on at least a portion of the surface thereof a second silicon oxide material which is different from the first silicon oxide material and is desired to be retained on the substrate, the second silicon oxide material being selected from the group consisting of doped silicon oxide, deposited silicon oxide, and thermally grown silicon oxide, and the first silicon oxide material comprising one or more members selected from the group consisting of silicon oxides formed as a result of ambient exposure of the substrate surfaces, silicon oxides formed as an incidental result of wet or gaseous chemical processing steps, and other trace silicon oxides, the method comprising
- placing the substrate in a gaseous environment comprising at least one fluorine containing gas which is free of hydrogen and which can be photodissociated, the gaseous environment being substantially free of plasma products, water, hydrogen, hydrogen fluoride and hydrogen containing organic compounds, and
- exposing the substrate to UV irradiation in the presence of the gaseous environment until the undesired material has been removed.
Dependencies are inferred from the claim text.